Generation and use of integrated circuit profile-based simulation information

ABSTRACT

An exemplary method and system for generating integrated circuit (IC) simulation information regarding the effect of design and fabrication process decisionn includes creating and using a data store of profile-based information comprising metrology signal, structure profile data, process control parameters, and IC simulation attributes. 
     An exemplary method and system for generating a simulation data store using signals off test gratings that model the effect of an IC design and/or fabrication process includes creating and using a simulation data store generated using test gratings that model the geometries of the IC interconnects. The interconnect simulation data store may be used in-line for monitoring electrical and thermal properties of an IC device during fabrication. Other embodiments include utilizing a metrology simulator and various combinations of a fabrication process simulator, a device simulator, and/or circuit simulator.

This application relates to co-pending U.S. patent application Ser. No.09/727,530 entitled “System and Method for Real-Time Library Generationof Grating Profiles” by Jakatdar, et al., filed on Nov. 28, 2000, ownedby the assignee of this application and incorporated herein by referenceand to co-pending U.S. patent application Ser. No. 09/764,780 entitled“Caching of Intra-Layer Calculations for Rapid Rigorous Coupled-WaveAnalyses” by Jakatdar, et al., filed on Jan. 26, 2000, owned by theassignee of this application and incorporated herein by reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present application relates to the general area of integratedcircuit (IC) manufacture and more particularly to methods and systemsfor creating and using a data store of profile-based simulationsinformation.

2. Related Art

With the demand for increasing clock rates and decreasing geometries ofIC structures, there is a need for rapid feedback on the effect of waferdesign and fabrication process decisions. In many traditional ICmanufacturing environments, the effect of a design decision or afabrication process change is frequently not immediately known by thedesigners or the process engineers until much later, resulting in costlyrework or unusable end products. IC design objectives drive the designactivity where masks and IC fabrication plans are produced andtransmitted to IC fabrication. IC fabrication produces the wafers thatare tested and that undergo finishing operations in IC testing andfinishing where flaws or shortcomings of the wafer are noted. Typically,some of the impact of design or process decisions is fed back to thedesign and fabrication groups at this point. After shipment of theproducts to the customers, additional product feedback that relate todesign and process alterations eventually get back to IC design. It iswell known in the industry that detection of a bad chip at the waferlevel is much cheaper than detecting the bad chip after manyend-products have been shipped to the customers. Thus, there is a needto provide information about the impact of design and process changes asearly as possible.

In a similar manner, there is a dearth of immediate feedback on designand process decisions to the manufacturing process control group. FIG. 1is a prior art architectural diagram illustrating the flow of data fromIC manufacturing process control to the various fabrication areas andfeedback from the fabrication areas to IC manufacturing process control.The IC manufacturing objectives 21 directs the IC manufacturing processcontrol 23 group with manufacturing plans 24 related to thin filmprocesses, deposition, or chemical mechanical polishing (CMP) 25,lithography 27, etching 29, photoresist (PR) stripping 33 and 35,implantation 31, and thermal processes 37 and IC testing and packaging39. Process feedback 34 and design and overall fabrication feedback 32are sent to the IC manufacturing process control 23 group. However, if adesign did not produce the desired results or a process change causedsome key critical dimension (CD) of the structures to be out of theacceptable ranges, the batch of wafers affected may have to bediscarded. Thus, there is a need to provide information in-line to theIC manufacturing process control group in order to minimize rejectedwafers and to detect and correct process control parameters from driftor process control parameter variations. Even with the use of currentdesign and fabrication process simulators, there is typicallyinsufficient information available early and/or in-line with thefabrication process.

There are several fabrication process, device, and circuit simulatorscurrently in use. Examples include software capable of interconnectsimulation, lithography simulation, implantation simulation, diffusionsimulation, oxidation simulation, deposition and etching simulation, CMPsimulation, deposition and reflow simulation, 2-dimensional processsimulation, and 3-dimensional fabrication process simulation, and otherscapable of simulating a step or series of steps of the IC fabricationprocess. Some simulators assume simple geometric shapes of ICstructures. However, data provided by AFM, Cross-Section SEM (X-SEM),and optical metrology systems indicate the cross-sections of structuresare complex shapes. These complex-shaped structures provide differentelectrical, thermal, and performance properties than the typicalgeometric shapes assumed. Other simulators attempt to model complexshapes with limited success due to the number of variables duringfabrication. For example, the structure shape is greatly influenced bythe process control parameters such as lithography numerical aperture,wavelength, focus exposure, post exposure bake (PEB) temperature, resistthickness, anti-reflective coating thickness, dielectric materials, andfabrication processes used.

As technology heads into the deep submicron geometries, (0.025 micron orless), there is a greater need for fast and accurate informationrelating to fabrication process attributes such as structure profiles,device attributes such as capacitance, inductance, and resistance andultimately circuit attributes. Similarly, there is a need for fast andreliable information for process control parameters such as PEBtemperature, focus, and exposure that generate the desired IC structureprofiles that in turn provide the desired device and circuit attributes.Thus, there is a need for a method and/or system for making theinformation on profile data, signals, process control parameters, andprocess attributes available during the fabrication process.Alternatively, given a structure profile or process attribute target,there is a need for rapid information on the process control parametervalues that would provide the desired results. For example, it isadvantageous to know the combination of PEB temperature, time, numericalaperture, and focus required to fabricate a structure with the desiredprofile that delivers the required electrical, thermal, and performanceproperties.

SUMMARY OF INVENTION

The invention includes a method and a system for creating and using adata store of profile-based simulation information. One embodimentincludes creating and using a data store of profile-based informationcomprising signals measured by a metrology device, structure profiledata, process control parameters, and fabrication attributes.Information from the data store may be used in-line during the design orfabrication process and/or in-situ with the fabrication processequipments.

Another embodiment is a method of generating an interconnect simulationdata store using test gratings that model the geometries ofinterconnects for the IC. The interconnect simulation data store may beused in-line for monitoring electrical and thermal properties of an ICduring fabrication. Alternatively, the simulation data store serverprovides information about the process control parameters that wouldsatisfy the required electrical properties of interconnects in the ICdesign for a given fabrication process.

Still another embodiment includes a method and system for generatingsimulation data store utilizing a metrology simulator and a fabricationprocess simulator. The fabrication process simulator may simulatelithography, implantation, diffusion, oxidation, deposition-and-etching,CMP, deposition-and-reflow, 2-dimensional process, 3-dimensional processsimulator or combination of these processes. Based on a range of processcontrol parameters and deviations of these process control parameters,structure profile data are generated using a fabrication processsimulator. The simulated structure profile data are converted intosignals using the metrology simulator. A simulation data store generatorcreates data store instances storing variations of the process controlparameters and associated signals, profile data, and fabricationattributes. Other embodiments include methods and systems for generatingsimulation data store utilizing a metrology simulator and a combinedprocess and device simulator or a combined process, device, and circuitsimulator. Information from the simulation data store may be usedin-line in-situ with each fabrication process step, providing up-to-datepertinent information to improve design, fabrication steps, yield, orinformation to correct process drifts.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a prior art architectural diagram illustrating the flow ofdata from IC manufacturing process control to the various fabricationareas and feedback from the fabrication areas to IC manufacturingprocess control.

FIG. 2 is a prior art architectural diagram contrasting the layerfeature profile of actual lithography process steps versus the featureprofile typically generated in a lithography simulator.

FIG. 3 is a prior art architectural diagram contrasting the interconnectcross-section of actual lithography and etching process steps versus thetypical interconnect cross-section generated in an interconnectsimulator.

FIG. 4 is an architectural diagram illustrating the use of an opticalmetrology system to determine the profile of periodic structures.

FIG. 5A is an architectural diagram illustrating the creation of asimulation data store using a device simulator in one embodiment of thepresent invention.

FIG. 5B is an architectural diagram illustrating the creation of aninterconnect simulation data store in one embodiment of the presentinvention.

FIG. 6A is an architectural diagram illustrating the creation of aprofile-based simulation data store using a fabrication processsimulator in one embodiment of the present invention.

FIG. 6B is an architectural diagram illustrating the creation of aprofile-based simulation data store using fabrication and devicesimulators in one embodiment of the present invention.

FIG. 6C is an architectural diagram illustrating the creation of aprofile-based simulation data store using process fabrication, device,and circuit simulators in one embodiment of the present invention.

FIG. 7A is an architectural diagram illustrating inquiry and in-line useof a simulation data store in one embodiment of the present invention.

FIG. 7B is an architectural diagram illustrating in-situ use of asimulation data store in various fabrication steps in one embodiment ofthe present invention.

FIG. 8A is a flow chart of the operational steps for creation of aprofile-based simulation data store using profile library data in oneembodiment of the present invention.

FIG. 8B is a flow chart of the operational steps for creation of aprofile-based simulation data store using test gratings in oneembodiment of the present invention.

FIG. 9A is a flow chart of operational steps for in-situ utilization ofa profile-based simulation data store in one embodiment of the presentinvention.

FIG. 9B is a flow chart of operational steps for online inquiryutilization of a profile-based simulation data store in one embodimentof the present invention.

FIG. 10 illustrates a data store format of profile-based simulation datastore in one embodiment of the present invention.

FIG. 11A is a graph showing the correlation of optical metrology CD andthe difference ΔW of the electric CD from the mask CD.

FIG. 11B are two graphs showing less variation of bottom CD and featuresidewall angle for a full-profile monitored fabrication process comparedto CD monitored or no monitoring of profile.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)

The invention includes a method and a system for creating and using adata store of profile-based simulation information. FIGS. 2 and 3illustrate the differences between simulation profiles versus actualprofiles of structures. FIGS. 4 to 8B depict embodiments of the creationprocess for the profile-based simulation data store. FIGS. 9A and 9Bdepict embodiments for using the profile-based simulation information.FIG. 10 illustrates one format of the simulation data store, while FIGS.11A and 11B represents empirical data that illustrate the utility of theconcepts and principles of the present invention.

FIG. 2 is a prior art architectural diagram contrasting the layerfeature profile of actual lithography process steps versus the featureprofile generated in a typical lithography simulator. A lithographysimulator 73 simulates the actual physical processes including spin/coat61, soft bake 63, exposure 65, post exposure bake 67, and development 69processes. The actual structure profile 71 may have a more complexprofile such as a rounded top and a footing at the bottom of thefeature, not the ideal rectangular shaped design structure profile 75typically indicated by the lithographic simulator 73. The electricalproperties of a circuit with non-rectangular structures, such astrapezoids, T-tops, and T-tops with undercut, rounded tops, with orwithout footing, are different from the electrical properties of simplegeometric-shaped structures typically assumed in some fabricationprocess simulators.

Similarly, FIG. 3 is a prior art architectural diagram contrasting theinterconnect cross-section of actual lithography, etching, andmetallization process steps versus the interconnect cross-sectiongenerated in a typical interconnect simulator. The fabricatedinterconnect cross-section 87 produced after the steps of interconnectdesign 81, fabrication 83, and testing 85 is typically irregular inshape. The shape of the fabricated interconnect is affected by thegeometries of the conductive material and the related dielectricmaterial. Electrical and thermal characteristics of the interconnectstructure with the fabricated interconnect cross-section 87 aredifferent from the electrical and thermal characteristics of arectangular design interconnect cross-section 91 typically assumed byinterconnect simulators 73. Given the current drive towards deepsubmicron process technologies and increasing clock rates, interconnectsessentially control the overall operating performance of high-speedsystems. The geometries of interconnects have significant impacts on theelectrical performance of the IC. Although atomic force microscopes(AFM) can provide interconnect profile information, AFM's are slow andcannot provide information on unpattemed layers. Critical dimensionscanning electron microscopes (CD-SEM) can provide critical dimensionsbut cannot provide profile information or data about unpattemed layers.

In order to facilitate the description of the present invention, anoptical metrology system is used to illustrate the concepts andprinciples. It is understood that the same concepts and principlesequally apply to the other IC metrology systems as will be discussedbelow. The metrology system may be an optical, electric, electron, ormechanical metrology system. Examples of optical metrology systemsinclude scatterometric devices such as spectroscopic ellipsometers,reflectometers, and the like. Examples of electron metrology systemsinclude CD-scanning electron microscope (CD-SEM), transmission electronmicroscope (TEM), and focused ion beam (FIB) devices. An example of amechanical metrology system includes an atomic force microscope (AFM)whereas an example of an electric metrology system includes acapacitance-measuring unit. As used in this application, a metrologysignal may be an optical signal, an ion beam, an electron beam, or otherlike signals.

FIG. 4 is an architectural diagram illustrating the use of an opticalmetrology system to determine the profile of periodic structures. Theoptical metrology system 40 includes a metrology signal source 41projecting a signal 43 at the target periodic structure 53 of a wafer 47mounted on a metrology platform 55. The metrology signal 43 is projectedat an incidence angle θ towards the target periodic structure 53. Thereflected signal 49 is measured by a metrology signal receiver 51. Thereflected signal data 57 is transmitted to a metrology profiler system59. The metrology profiler system 59 compares the measured reflectedsignal data 57 against a library of calculated reflected signal datarepresenting varying combinations of critical dimensions of the targetperiodic structure and resolution. The library instance best matchingthe measured reflected signal data 57 is selected. The profile andassociated critical dimensions of the selected library instancecorrespond to the cross-sectional profile and critical dimensions of thefeatures of the target periodic structure 53. A similar opticalmetrology system 40 is described in co-pending U.S. patent applicationSer. No. 09/727,530 entitled “System and Method for Real-Time LibraryGeneration of Grating Profiles” by Jakatdar, et al., filed on Nov. 28,2000, which issued as U.S. Pat. No. 6,768,983 on Jan. 27, 2004, owned bythe assignee of this application and incorporated herein by reference.

FIG. 5A is an architectural diagram illustrating the creation of asimulation data store using a device simulator in one embodiment of thepresent invention. The profile-based creation of a simulation data store100 includes a fabrication process designer 101 where the series of ICfabrication steps are laid out. A set of test grating masks is designedin the test grating mask designer 103 to capture key features orcharacteristics of the area of interest. For example, if the area ofinterest is capacitance of interconnects, then the set of test gratingmasks designed captures the various interconnect geometric information.Interconnect geometric information include profiles of structures in thewafer. The IC fabricator 105 uses the set of test grating masks to maketest structures that are measured by a metrology device 107. Themetrology device 107, which may be an optical metrology device or anon-optical metrology device, measures the signals off the test gratingsand transmits the measured signals to the profiler application server109. The profiler application server 109 compares the measured signalsoff the test structures to the calculated signals in a profile library110 covering a range of expected structures profile critical dimensionsand resolutions. The profiler application server 109 selects the bestmatching profile library instance from the calculated signals of theprofile library 110. In one embodiment, the best matching measureddiffracted metrology signal is one with the least error compared to thediffracted metrology signal. Several optimization procedures areavailable to minimize the error, such as simulated annealing, describedin “Numerical Recipes,” section 10.9, Press, Flannery, Teulkolsky &Vetterling, Cambridge University Press, 1986; which is incorporated byreference. One error metric that produces appropriate results is thesum-of-the-squared-difference error, where the optimization procedureminimizes the error metric between the measured diffracted metrologysignal and the calculated diffracted metrology signal. The detailedprocedure for creating calculated signals for a profile library for arange of structure profile critical dimensions and resolutions andselecting the best matching library instance from the calculated signalslibrary is contained in co-pending U.S. patent application Ser. No.09/727,530 entitled “System and Method for Real-Time Library Generationof Grating Profiles” by Jakatdar, et al., filed on Nov. 28, 2000, whichissued as U.S. Pat. No. 6,768,983 on Jan. 27, 2004, and is incorporatedherein in its entirety by reference.

Still referring to FIG. 5A, the profile data of the best matchingprofile library instance are transmitted to the device simulator 113.Profile data comprises critical dimensions, profile shape description,and profile graphic representation. Critical dimensions are typicallyexpressed as measurement dimensions, for example, width of 50nanometers. Alternatively, critical dimensions are also expressed as apercent of another critical dimension, for example, 80% height of toprounding meaning the structure top starts rounding at 80% of thestructure's height. An example of profile shape description istrapezoidal with top rounding profile. An example of profile graphicrepresentation is a bit map of the profile. The device simulator 113 maybe any type of device simulator simulating electrical, thermal, noise,3D effects, steady or transient state signal, leakage and/or opticalcharacteristics. Examples of device simulators are Raphael.™, Medici.™,ATLAS.™, and TMA-Visual.™ from companies such as Avant!, TechnologyModeling Associates, and Silvaco International. The profile criticaldimensions of the best matching library instance from the calculatedsignals library is extracted by the profiler application server 109 andtransmitted to the device simulator 113. The device simulator 113creates as output the set of process control parameters used in thesimulation run and the resulting device attributes. For example, if thedevice simulator is an interconnect simulator, the input may be the topand bottom CD's in nanometers, and the sidewall angle in degrees in aformat required by the interconnect simulator used. The output of thedevice simulator 113 is device attributes including resistance in ohms,capacitance in farads, and inductance in henrys. The simulation datastore generator 111 creates a data store instance comprising signals,profile data, simulation type, and device attributes associated with thespecific device simulation. Simulation type is the characterization ofthe simulation being performed, for example device simulation. A partiallist of simulation types is included in FIG. 10.

FIG. 5B is an architectural diagram illustrating the creation of aninterconnect simulation data store in one embodiment of the presentinvention. The profile-based creation of a simulation data store 120includes a fabrication process designer 121 where the series of ICinterconnects are laid out. A set of test grating masks is designed inthe test grating mask designer 123 that captures the variousinterconnect geometric information. Interconnect geometric informationinclude profiles of structures in the wafer. The IC fabricator 125 usesthe set of test grating masks to make test structures that are measuredby a metrology device 127. The metrology device 127, which may be areflectometer, an ellipsometer or other non-optical metrology device,measures the diffracted signals off the test structures and transmitsthe measured signals to the profiler application server 129. Theprofiler application server 129 compares the measured signals off thetest structures to the calculated signals in a library 130 covering arange of expected structures profile critical dimensions andresolutions. The profiler application server 129 selects the bestmatching library instance from the library. The profile CD's of the bestmatching library instance is extracted by the profiler applicationserver 129 and transmitted to the interconnect simulator 133. Theinterconnect simulator 133 creates as output the set of process controlparameters used in the simulation run and the device attributes.Examples of interconnect simulators include Raphael.™, QuickCap.™, andAtlas.™. The output of the interconnect simulator 133 includes deviceattributes such as resistance in ohms, capacitance in farads, andinductance in henrys. The simulation data store generator 131 creates adata store instance in the simulation data store 135 for each testgrating comprising signals, profile data, simulation type, and deviceattributes. Simulation type in this case is interconnect devicesimulation and the device attributes are those associated with theinterconnect device simulation. An illustrative layout of simulationdata store is depicted in FIG. 10.

For FIGS. 6A to 6C, similar figure objects are identified with the samenumbers in order to facilitate the description of the embodiments. FIG.6A is an architectural diagram illustrating the creation of aprofile-based simulation data store using a fabrication processsimulator in one embodiment of the present invention. The profile-basedcreation of a simulation data store 130 starts with the input of processcontrol parameters 132 into the fabrication process simulator 133.Examples of process control parameters include exposure time, numericalaperture, and PEB temperature in a lithographic process simulation. Thefabrication process simulator 133 may be any type of process simulatorsimulating a thin film, lithography, implantation, diffusion, oxidation,deposition, etching, CMP process or combination of processes. Using theprocess control parameters 132, the fabrication process simulator 133creates the fabrication attributes 134 including the geometries of thelayer structures. The process control parameters 132 and fabricationattributes 134 are transmitted to the simulation data store generator139. The fabrication attributes 134 are transmitted to the metrologysimulator 137. Fabrication attributes that pertain to the profiles ofthe structures are used by the metrology simulator 137 to generatediffracted signals corresponding to the profile of the structuregenerated by the fabrication process simulator 133. For example, thefabrication process simulator 133 may be a lithography, etch, or acombined lithography and etch simulator. The process control parameters132 may include film thickness, bake time, exposure, PEB time, PEBtemperature, rinse time, and/or etch flow rate and type of etchant.Fabrication attributes 134 may include the patterned structure profileshape and critical dimensions (CD's) such as top CD, bottom CD, height,and/or sidewall angle.

Still referring to FIG. 6A, from the fabrication attributes 134, themetrology simulator 137 extracts the profile data and calculates signalscorresponding to the signals off a grating with the transmitted profileshape and CD's. In a case where the metrology simulator 137 is anoptical metrology simulator, the signals are simulated diffractionsignals. For a description of the calculation of simulated diffractionsignals, refer to co-pending U.S. patent application Ser. No. 09/764,780entitled “Caching of Intra-Layer Calculations for Rapid RigorousCoupled-Wave Analyses” by Jakatdar, et al., filed on Jan. 26, 2000,which has been expressly abandonded, which is incorporated in itsentirety herein by reference. The simulation data store generator 139processes the process control parameters 132 and input data from thefabrication process simulator 133 and the metrology simulator 137 tocreate the simulation data store 149 instances. The simulation datastore instance comprises signals, profile data, simulation type, processcontrol parameters, and fabrication attributes associated with theprocess simulation. Simulation type is the characterization of thesimulation being performed, for this example, fabrication processsimulation. A partial list of simulation types is included in FIG. 10.

FIG. 6B is an architectural diagram illustrating the creation of aprofile-based simulation data store using fabrication and devicesimulators in one embodiment of the present invention. The profile-basedsystem for creating the simulation data store 140 using a processsimulator and a device simulator is similar to the process described forFIG. 6A except that the output from the fabrication process simulator133 including fabrication attributes is also transmitted to a devicesimulator 135. The device simulator 135 utilizes the fabricationattributes to perform a device simulation and transmits deviceattributes 136 to the simulation data store generator 139. Thesimulation data store generator 139 processes the input data from thefabrication process simulator 133 comprising process control parameters132 and fabrication attributes 134, data from the metrology simulator137 comprising calculated diffracted signal 142, and data from thedevice simulator 135 comprising device attributes 136 to create thesimulation data store 149. The simulation data store 149 instancescomprises signals, profile data, simulation type, process controlparameters, fabrication attributes, and device attributes. Simulationtype in this case is a combined fabrication-process-and-devicesimulation. For example, the fabrication process simulator may be acombined lithography-and-etch process simulator whereas the devicesimulator may be an interconnect simulator. Other devices that may besimulated include diodes, transistors, optical devices, power devices,or photo detectors. An illustrative layout of simulation data store isdepicted in FIG. 10. The simulation data store for this example would beable to provide responses to several types of queries with a given data.If the given data is the desired capacitance of a device, the simulationdata store can provide the required profile(s) of the interconnects.Similarly, if the given data is a profile of the interconnect, thesimulation data store can provide the corresponding process controlparameters such as numerical aperture, bake time, PEB temperature, etchtime or type of etchant. Many other variations of the given datadiscussed later can be formulated to give the desired query response.

Still referring to FIG. 6B, the fabrication process simulator 133 andthe device simulator 135 may be separate objects or combined in a singleobject or a single software package. Examples of combined process anddevice simulators include Victory.™ from Silvaco International andMicrotec.™ from Syborg Systems, Inc.

FIG. 6C is an architectural diagram illustrating the creation of aprofile-based simulation data store using fabrication process, device,and circuit simulators in one embodiment of the present invention. Theprofile-based system for creating the simulation data store 150 using afabrication process simulator, a device simulator, and a circuitsimulator is similar to the process described for FIG. 6B except thatthe output from the device simulator 135 including device attributes 136are also transmitted to a circuit simulator 141. The circuit simulator141 utilizes the device attributes of several devices that form thecircuit. For example, a transmission line includes several interconnectdevices to form a circuit. Examples of circuits that may be simulatedinclude transmission lines, resistors, capacitors, inductors,amplifiers, switches, diodes, or transistors. The combination ofselected devices to form a circuit are simulated, the simulationscreating device attributes 136 that are used to perform a circuitsimulation with the circuit simulator 141. The circuit simulator 141generates and transmits circuit attributes 138 to the simulation datastore generator 139. The simulation data store generator 139 processesthe input data from the fabrication process simulator 133 comprisingprocess control parameters 132 and fabrication attributes 134, data fromthe metrology simulator 137 comprising calculated diffracted signal 142,and data from the device simulator 135 comprising device attributes 136,and data from the circuit simulator 141 comprising circuit attributes138 to create the simulation data store 149. The simulation data store149 instance comprises signals, profile data, simulation type, processcontrol parameters, fabrication attributes, device attributes, andcircuit attributes. Simulation type is the characterization of thesimulation being performed, for this example, combined fabricationprocess, device, and circuit simulation. A partial list of simulationtypes is included in FIG. 10.

Still referring to FIG. 6C, the fabrication process simulator 133,device simulator 135, and circuit simulator 141 may be separate objectsor combined in a single object or a single software package. Examples ofcircuit simulators include SPICE.™, various adaptations of SPICE.™,SPECTRE.™, APLAC.™, and PROTOLAB.™. An example of a combined totalprocess simulator is ATHENA.™ from Silvaco International.

The concepts and principles of the present invention will apply to othercombination simulators such as a combined device-and-circuit simulation.Creation of the simulation data store would be done in a similar manner.Similarly, the device simulator and circuit simulator may be separateobjects or combined in a single object or a single software package.Examples of combined device-and-circuit simulators include MEDICI.™,TOPSPICE.™, CIDER.™, and SIMPLORER.™.

FIG. 7A is an architectural diagram illustrating inquiry and in-line useof a simulation data store in one embodiment of the present invention.An inquiry 203 from an inquiry device 201 is transmitted to a simulationdata store server 207 that analyzes the inquiry and accesses theinstance(s) of the simulation data store 215 and formulates the response205. The simulation data store server 207 may also be invoked by anin-line query 209 generating a response 213. In one application, theinquiry 209 is from an in-line query device 211 generating a response213. The inquiry 209 comprises the type of inquiry and query given data.Depending on the type of inquiry and query given data, the simulationdata store server 207 retrieves the appropriate instance(s) of thesimulation data store 215 and formats and transmits the response 213.The in-line query device 211 may be part of a computer system or part ofan IC fabrication system. The inquiry device 201 may be a stand-alonedevice or part of a system. Furthermore, the inquiry device 201 may belocal or accessible through a network.

FIG. 7B is an architectural diagram illustrating the in-situ use of asimulation data store in various fabrication steps in one embodiment ofthe present invention. A simulation data store server 250 coupled to asimulation data store 255 may be part of a fabrication system, thesimulation data store server 250 providing immediate in-situprofile-based simulation information. The simulation data store server250 may be coupled to a thin film, deposition or CMP 225, lithography227, etch 229, PR stripping after etch 233, PR stripping afterimplantation 235, implantation 231, and/or thermal processes 237devices. The simulation data store server 250 may be locally or remotelyconnected to the fabrication devices. The simulation data store server250 may be several separate servers or one centralized server. Teststructures or test gratings in a wafer may be measured by an integratedmetrology device (not shown) during or after a fabrication step. Themetrology measurement generates measured signals that may be used as thequery given data to the simulation data store server 250. The simulationdata store server 250 generates an in-situ/in-line response based on theinquiry type and query given data. For example, during or after aphotoresist stripping step, if the inquiry type from the fabricationdevice is for electrical properties of the IC structure modeled by thetest grating and the query given data is the diffracted signal off thetest grating, the simulation data store server 250 would formulate aresponse comprising conductance, capacitance, and/or resistance of theIC structure modeled by the test grating. In another example after alithography step, if the inquiry type is for process control parametersassociated with the measured signals off the test grating, thesimulation data store server 250 would formulate a response comprisingbake time, bake temperature, focus, and PEB time and temperature. Aswill be discussed below, many other combinations of inquiry type andquery given data can be transmitted to the data store server 250 to getthe specific response required.

FIG. 8A is a flow chart of the operational steps for creation of aprofile-based simulation data store using profile library data in oneembodiment of the present invention. The expected profile data rangesand resolutions of profile shapes of patterned structures for theprofile library are determined 300. For example, a trapezoidal profileshape may be characterized by the top CD, bottom CD, grating thickness,height and width at the inflection point, and underlying thickness innanometers. The profile data ranges would include a minimum, maximum,and resolution for the top CD, bottom CD, grating thickness, height andso on. The profile data ranges at various resolutions of profile shapesare used to calculate the simulated diffracted signals and to create theprofile library 320. The detailed procedure for creating a profilelibrary for a range of structure profile critical dimensions andresolutions is contained in co-pending U.S. patent application Ser. No.09/727,530 entitled “System and Method for Real-Time Library Generationof Grating Profiles” by Jakatdar, et al., filed on Nov. 28, 2000, whichissued as U.S. Pat. No. 6,768,983 on Jan. 27, 2004, is incorporatedherein in its entirety by reference.

The profile data ranges for the expected profile shapes are convertedinto the device simulator input 330. For example, if the devicesimulator is an interconnect simulator, the expected profile shapedimensions are converted into the format required by the selectedinterconnect simulator, like Raphael.™. Using the converted devicesimulator input, the device simulator is invoked 350 generating thedevice attributes. Continuing with the interconnect simulator example,the interconnect simulator is invoked using the converted profile dataas the interconnect simulator input, generating device attributescomprising electric and thermal properties such as resistance,capacitance, inductance, potential, temperature, and current densitydistribution. A simulation data store instance is created comprisingdiffracted signals, profile data, simulation type, and device attributes360. Again continuing with the interconnect example and assuming anoptical metrology device, the simulation data store instance createdincludes signals such as tangent (Ψ) and cosine (Δ) data for awavelength range for an ellipsometer or reflected light intensity for awavelength range for a reflectometer, the wavelength range andmeasurement points dependent on the manufacturer of the opticalmetrology device. In addition, the simulation data store instancecreated also includes the associated profile data comprising profileshape CD's, simulation type being interconnect device simulation,profile data comprising top CD, bottom CD, grating thickness, height andwidth at inflection point, and underlying thickness; and deviceattributes such as resistance, capacitance, inductance, potential,temperature, and current density distribution. The simulation data storecreation process is iterated until the simulations are complete 370.

FIG. 8B is a flow chart of the operational steps for creation of aprofile-based simulation data store using test gratings in oneembodiment of the present invention. The set of process controlparameters for the type of simulations desired is selected 400. Usingthe selected set of process control parameters, the fabrication processsimulator is invoked 410, generating fabrication attributes. Thefabrication attributes are converted into profile data comprisingprofile shape and critical dimensions 420. A metrology simulator usesthe profile shape and critical dimensions to calculate diffractedsignals 430. Data including the process control parameters, the profiledata, the calculated signals are used to create a simulation data storeinstance 435. For example, if the type of fabrication process simulationis lithography, the set of process control parameters may include valuesof the bake time, bake temperature, focus, PEB time, and/or rinsetemperature. The fabrication attributes generated by the fabricationprocess simulation include profile data, comprising profile shape andgeometry of the structure. The profile shape and geometry is convertedinto the CD's required by the metrology simulator to calculate thereflected signals. If the profile shape is trapezoidal profile with toprounding and bottom footing, the CD's include the feature footing bottomwidth, trapezoidal bottom width, total height, trapezoidal width, andthe rounding top width.

Fabrication attributes generated by the fabrication process simulatorare converted to the format compatible with the device simulatorrequirements 440. The device simulator is invoked using the convertedfabrication attributes, generating device attributes 445. The simulationdata store instances are updated with the device attributes 450. In oneembodiment, the fabrication process simulator and the device simulatorare combined in a single package, removing the requirement of conversionof input parameters into compatible formats. Several devices that form acircuit or part of a circuit may be grouped together for a circuitsimulation. For example, several IC components such as gates, contactholes, vias, and pads forming a circuit or part of a circuit are groupedtogether for a circuit simulation. Device attributes for each of thesegrouped devices are converted into a format compatible with the circuitsimulator requirements 460. The circuit simulator is invoked, using theconverted device attributes, generating circuit attributes 465. Examplesof circuit attributes are voltage and current as function of time, noiseanalysis, distortion analysis, and sensitivity analysis. The appropriatesimulation data store instances are updated with the correspondingcircuit attributes 470.

FIG. 9A is a flow chart of operational steps for in-situ utilization ofa profile-based simulation data store in one embodiment of the presentinvention. The signals off the test gratings of a wafer are measuredwith a metrology device 600. A best matching signal instance in theprofile-based simulation data store is selected 610. The simulation typeis determined 620 in order to access the simulation data associated withthe best matching simulation data store instance 630. The requestedinformation from the profile-based simulation data store is displayed640. Process control parameters, signals, profile data, fabricationattributes, device attributes, and/or circuit attributes may bedisplayed.

For example, test gratings in a wafer after a lithography and etchprocess are measured with an optical metrology device, generatingmeasured diffracted spectra. The best matching instances of thesimulation data store compared to the diffracted spectra of the testgratings are selected and profile data of the test gratings areextracted. The requested information comprises electrical deviceattributes associated with an interconnect device simulation.Capacitance, resistance, and inductance information from the simulationdata store corresponding to the profile data of the test gratings aredisplayed.

FIG. 9B is a flow chart of operational steps for online inquiryutilization of a profile-based simulation data store in one embodimentof the present invention. The type of inquiry and query given data isvalidated against the profile-based simulation data store 700. Instancesof the profile-based simulation data store meeting the inquiry type andquery given data are selected 720. The requested information from theselected instances of the profile-based simulation data store isdisplayed 730. For example, if the inquiry type is for process controlparameters of a lithography simulation and the query given data iselectrical conductivity, displayed information may include profile CD'sand data on the focus, exposure, PEB temperature, resist thickness, andanti-reflective coating thickness for the lithography process.Conversely, if the inquiry type is for device attributes and the querygiven data are diffracted signals, displayed information may includecapacitance and other device attributes. Alternatively, if the inquiryis for profile data of a via and the query given data consists ofvoltage and current as a function of time for a circuit, the displayeddata may include the profile shape and CD's of the profile. It isunderstood that a person knowledgeable in the art can formulate a numberof different inquiry types and various combinations of query given datato get the right information displayed from the profile-based simulationdata store.

FIG. 10 illustrates a simulation data store format of a profile-basedsimulation data store in one embodiment of the present invention. Datastore format 800 includes signals 801, profile data 803, simulation datasegments 804 comprising simulation type 805, process control parametersor input parameters 807, and fabrication, device, and/or circuitattributes 809. For a given signal 801 and corresponding profile data803, there may be several simulation data segments 804 of simulationtype 805, process control parameters or input parameters 807, andfabrication, device, and/or circuit attributes 809. Simulation type 805includes fabrication process simulation, device simulation, circuitsimulation, combined fabrication and device simulation, combined deviceand circuit simulation, or combined fabrication, device, and circuitsimulation. Examples of fabrication process simulation includelithography, etch, implantation, oxidation, CMP, diffusion, depositionand etching, deposition and reflow, 2-dimensional process, 3-dimensionalprocess simulations, plus various combinations of the foregoingprocesses. Examples of device simulation include interconnect,electrostatic discharge, optical device, power device, compound device,and other device simulations. Examples of circuit simulation includetransient signal, signal integrity, noise, and other circuit simulation.

FIG. 10 illustrate examples of simulation data store format for aninterconnect device simulation and a combined fabrication process anddevice simulation. In Example 1, an interconnect device simulation, thesignal is expressed in values representing optical metrology measurementdata using an ellipsometer. This example has one simulation data segmentwhere the key input parameter is profile data and the device attributesare capacitance, inductance, and resistance. Example 2 represents asimulation data store instance storing data from two linked simulations,namely, a lithography and etch fabrication process simulation linked toan interconnect device simulation. Each simulation has a correspondingsimulation data segment. The fabrication process simulation generatedthe fabrication attributes that are used as input to the devicesimulation. It is understood that to one knowledgeable in the art, thevarious combinations of fabrication process, device, and circuitsimulations would result in corresponding combinations of simulationdata segments following the same concepts and principles illustrated inthe foregoing examples.

FIG. 11A is a graph showing the correlation of optical metrology CD andthe difference ΔW of the electric CD from the mask CD. TheCD_(OPTICAL METROLOGY) is the critical dimension of a structure asdetermined by an optical metrology device such as an ellipsometer or areflectometer. CD_(MASK) is the critical dimension designed in a mask,such as top CD of a structure. CD_(ELECTRIC) is the critical dimensionof the structure based on the electrical properties and is derivedstarting with the basic equation: V/I=R where V is the voltage, I is thecurrent, and R is the resistance. The resistance R is equal toresistivity p divided by the area A:R=ρ/A=ρ/H*CD _(ELECTRIC)

where H is the height of the structure and CD_(ELECTRIC) is theeffective width. Given that the resistivity ρ of a structure materialand H are generally constant, CD_(ELECTRIC) is the variable thatcontrols the electrical resistance of the structure. The graph 811 inFIG. 11A shows close correlation of optical metrology CD to ΔW, thedifference between the electric CD from the mask CD, the weightedaverage graph being a straight line. This empirical data illustrates theutility of profile-based simulation data stores as described in thevarious embodiments.

FIG. 11B are two graphs showing less variation of bottom CD and featuresidewall angle for a full-profile monitored fabrication process comparedto CD-only monitored or no profile monitoring of the fabricationprocess. Empirical data obtained using an exponentially weighted movingaverage controller and first order integrated moving average disturbancegenerator indicate that full-profile control 821 of the bottom CD in alithographic simulation provided the least variations of bottom CDcompared to CD-only control 825 or no control 823 shown in the topgraph. Similarly, the bottom graph based on empirical data indicate thatfull-profile control 835 of the sidewall angle in a lithographicsimulation provided the least variations of sidewall angle compared toCD-only control 833 or no control 831. Similar to FIG. 11A, these graphsthat are based on empirical data illustrate the utility of profile-basedsimulation data stores as described in the various embodiments.

There are many uses for a profile-based simulation data store in ICmanufacturing. The concepts and principles of the present invention areapplicable to simulations of IC fabrication process steps, devices, orcircuits. As will be apparent to a person knowledgeable in the art, theconcepts and principles of creating and using a profile-based simulationdata store also applies to combinations of fabrication process anddevice simulations, device and circuit simulations, or fabricationprocess, device, and circuit simulations.

Foregoing described embodiments of the invention are provided asillustrations and descriptions. They are not intended to limit theinvention to precise form described. In particular, it is contemplatedthat functional implementation of invention described herein may beimplemented equivalently in hardware, software, firmware, and/or otheravailable functional components or building blocks.

Other variations and embodiments are possible in light of aboveteachings, and it is thus intended that the scope of invention not belimited by this Detailed Description, but rather by Claims following.

1. A method of creating a profile-based simulation data store for anintegrated circuit utilizing one or more simulations, the methodcomprising: simulating one or more fabrication processes using aselected set of process control parameters, the fabrication processsimulations generating fabrication attributes; generating calculatedsignals with a metrology simulator, the metrology simulator usingprofile data from the fabrication attributes, wherein the calculatedsignals are simulations of diffraction signals measured using an opticalmetrology device, the profile data comprising profile shapes andcritical dimensions of structures resulting from the one or morefabrication process simulations; and creating simulation data storeinstances, the instances including profile data and correspondingcalculated signals, simulation types, and associated process controlparameters and fabrication attributes; wherein the simulation types arecharacterizations of the one or more simulations performed.
 2. Themethod of claim 1 wherein simulating one or more fabrication processescomprises: simulating a thin film, deposition or chemical mechanicalpolishing process using a selected first set of process controlparameters; and simulating lithography process using a selected secondset of process control parameters.
 3. The method of claim 1 whereinsimulating one or more fabrication processes comprises: simulating alithography process using a selected first set of process controlparameters; and simulating an etch process using a selected second setof process control parameters.
 4. The method of claim 1 whereinsimulating one or more fabrication processes comprises: simulating alithography process using a selected first set of process controlparameters; and simulating an implantation process using a selectedsecond set of process control parameters.
 5. The method of claim 1wherein simulating one or more fabrication processes comprises:simulating an etch process using a selected first set of process controlparameters; and simulating a photoresist stripping process using aselected second set of process control parameters.
 6. The method ofclaim 1 wherein simulating one or more fabrication processes comprises:simulating an implantation process using a selected first set of processcontrol parameters; and simulating a photoresist stripping process usinga selected second set of process control parameters.
 7. A method ofcreating a profile-based simulation data store for an integrated circuitutilizing one or more simulations, the method comprising: simulating oneor more devices using a selected set of input parameters, the devicesimulations generating device attributes, the set of input parametersincluding profile data corresponding to the one or more simulateddevices; generating calculated signals with a metrology simulator, themetrology simulator using profile data corresponding to the one or moresimulated devices, and wherein the calculated signals are simulations ofdiffraction signals measured using an optical metrology device; andcreating simulation data store instances, the instances includingprofile data and corresponding calculated signals, simulation types,process control parameters, and fabrication attributes; wherein thesimulation types are characterizations of the one or more simulationsperformed.
 8. The method of claim 7 wherein the selected set of inputparameters comprises a profile library having profile data, the profiledata including profiles of the one or more devices simulated.
 9. Amethod of creating a profile-based simulation data store for anintegrated circuit utilizing one or more simulations, the methodcomprising: simulating one or more circuits using a selected set ofinput parameters, a circuit having one or more devices, the circuitsimulations generating circuit attributes, the set of input parametersincluding profile data corresponding to the one or more devices of thesimulated one or more circuits; generating calculated signals with ametrology simulator, the metrology simulator using profile datacorresponding to the one or more devices of the simulated one or morecircuits, and wherein the calculated signals are simulations ofdiffraction signals measured using an optical metrology device; andcreating simulation data store instances, the instances includingcalculated signals, profile data, simulation types, process controlparameters, and circuit attributes; wherein the simulation types arecharacterizations of the one or more simulations performed.
 10. Themethod of claim 9 wherein the one or more circuits simulated includetransmission lines, resistors, capacitors, inductors, amplifiers,switches, diodes, or transistors.
 11. A method of creating aprofile-based simulation data stare for an integrated circuit utilizingone or more simulations, the method comprising: simulating one or morefabrication processes using a selected set of process controlparameters, the fabrication process simulations generating fabricationattributes; generating calculated signals with a metrology simulator,the metrology simulator using profile data from the generatedfabrication attributes, wherein the calculated signals are simulationsof diffraction signals measured using an optical metrology device, theprofile data comprising profile shapes and critical dimensions ofstructures resulting from the one or more fabrication processsimulations; simulating one or more devices using profile data generatedby the one or more simulated fabrication processes; and creatingsimulation data store instances, the instances including profile datafrom the generated fabrication attributes, corresponding calculatedsignals, simulation types and associated process cordial parameters anddevice attributes; wherein the simulation types are characterizations ofthe one or more simulations performed.
 12. The method of claim 11wherein the one or more fabrication processes simulated include a,lithography simulation and an etch simulation and wherein the one ormore device simulations include an interconnect simulation.
 13. A methodof creating a profile-based simulation data store for an integratedcircuit, the method comprising: simulating one or more devices using aselected set of input parameters, the device simulations generatingdevice attributes, the set of input parameters including profile data ofthe one or more simulated devices; generating calculated signals with ametrology simulator, the metrology simulator using profile data of theone or more simulated devices, and wherein the calculated signals aresimulations of diffraction signals measured using an optical metrologydevice; simulating one or more circuits using the generated deviceattributes from the one or more device simulations as input parameters,the circuit simulations generating circuit attributes; and creatingsimulation data store instances, the instances including profile dataand corresponding calculated signals, simulation types end associatedinput parameters, device attributes, and circuit attributes; wherein thesimulation types are characterizations of the one or more simulationsperformed.
 14. The method of claim 13 wherein the one or more devicesimulations include a power device simulation and an interconnectsimulation.
 15. The method of claim 13 wherein the one or more circuitsimulations include a transmission line simulation and an amplifiersimulation.
 16. A method of creating a profile-based simulation datastore for an integrated circuit utilizing one or more simulations, themethod comprising: simulating one or more fabrication processes using aselected set of process control parameters, the fabrication processsimulations generating fabrication attributes; generating calculatedsignals with a metrology simulator, the metrology simulator usingprofile data from the generated fabrication attribute, wherein thecalculated signals are simulations of diffraction signals measured usingan optical metrology device, the profile data comprising profile shapesand critical dimensions of structures resulting from the one or morefabrication process simulations; simulating one or more devices usingprofile data generated by the one or more simulated fabricationprocesses; simulating one or more circuits using the generated deviceattributes from the one or more device simulations as input parameters,the circuit simulations generating circuit attributes; and creatingsimulation data store instances, the instances including profile data,corresponding calculated signals, simulation types, and associatedprocess control parameters, fabrication attributes, device attributes,and circuit attributes; wherein the simulation types arecharacterizations of the one or more simulations performed.
 17. Themethod of claim 16 wherein the one or more fabrication processsimulations include a lithography simulation, the one or more devicesimulation includes an interconnect simulation, and the one or morecircuit simulation include a transmission line simulation.
 18. A methodof creating a profile-based simulation data store for an integratedcircuit, the method comprising: measuring one or more test gratings withan optical metrology device wherein the test gratings model the effectof an integrated circuit design and/or fabrication process; generatingmeasured diffraction signals with the optical metrology device;converting the measured diffraction signals into profile datacorresponding to the measured test gratings; simulating one or moredevices using the convened profile data as a set of input parameters,the device simulations generating device attributes; and creatingsimulation data store instances, the instances including profile data,corresponding calculated diffraction signals, simulation types, andassociated device attributes, wherein calculated diffraction signals aresimulations of diffraction signals measured using the optical metrologydevice; wherein the simulation types are characterizations of the one ormore simulations performed.
 19. The method of claim 18 whereinconverting the measured diffraction signals into process controlparameters further comprises: comparing the measured diffraction signalsoff the test gratings to instances of a library of calculateddiffraction signals, the instances of the library of calculateddiffraction signals having data elements comprising calculateddiffraction signals and profile data; selecting corresponding bestmatching instances in the library of calculated diffraction signals; andaccessing profile data from the selected best matching instances of thelibrary of calculated diffraction signals.
 20. The method of claim 18wherein the one or more device simulations are interconnect simulations.21. The method of claim 18 wherein measuring the test grating furthercomprises: designing the test gratings to capture interconnect geometricconfigurations of the integrated circuit; fabricating the designed testgratings; and measuring the fabricated test gratings with the metrologydevice.
 22. The method of claim 18 wherein the device attributes includeresistance, inductance, capacitance, potential, temperature, and currentdensity distribution of the interconnect.
 23. A method of real-time useof simulation data store, the method comprising: measuring a rating withan optical metrology device, the grating modeling an interconnectgeometry of an integrated circuit, the measurement generating a measureddiffraction signal; and obtaining interconnect electrical propertiesand/or thermal properties corresponding to the measured diffractionsignal off the grating, wherein obtaining interconnect electricalproperties and/or thermal properties corresponding to the measureddiffraction signal off the grating further comprises: accessing asimulation data store, the simulated data store storing instances havingdata elements comprising calculated diffraction signals and deviceattributes, the device attributes including interconnect electricalproperties and/or thermal properties, wherein the calculated diffractionsignals simulate diffraction signals measured using the opticalmetrology device; comparing the measured diffraction signal to thecalculated diffraction signals in the instances of the simulation datastore; selecting a best matching instance of the simulation data store;and accessing the interconnect electrical properties and/or thermalproperties associated with the best matching instance of the simulateddata store.
 24. The method of claim 23 wherein the interconnectelectrical properties include capacitance, inductance, and resistance.25. A method of creating a profile-based simulation data store for anintegrated circuit utilizing a metrology simulator, the methodcomprising: performing fabrication process simulations using a set ofprocess control parameters, the fabrication process simulationsgenerating a set of fabrication attributes and a set of structureprofile data; calculating a set of simulated signals corresponding tothe set of structure profile data using a metrology simulator, whereinthe simulated signals are simulations of diffraction signals measuredusing an optical metrology device; and creating instances of asimulation data store, each instance of the simulation data store havingdata elements comprising profile data and corresponding calculatedsignals, simulation types, and associated process control parameters andfabrication attributes; wherein the simulation types arecharacterizations of the simulations performed.
 26. The method of claim25 wherein the fabrication process simulation is a lithographysimulation.
 27. The method of claim 25 wherein the fabrication processsimulation is a combined lithography and etch simulation.
 28. The methodof claim 25 wherein the fabrication process simulation is animplantation simulation, diffusion simulation, oxidation simulation,deposition and etching simulation, chemical mechanical polishingsimulation, deposition and reflow simulation, 2-dimensional processsimulation, or 3-dimensional fabrication process simulation.
 29. Themethod of claim 25 wherein the metrology simulator is an opticalmetrology simulator.
 30. A system for creating a profile-basedsimulation data store for an integrated circuit, the system comprising:a profiler application server configured to: compare a measureddiffraction signal off a test grating in a wafer to calculateddiffraction signals in instances of a calculated diffraction signalslibrary, the library instances storing data elements comprisingcalculated diffraction signals and profile data, and select a bestmatching instance of the library of calculated diffraction signals; afabrication process simulator configured to: simulate one or morefabrication processes, and generate fabrication attributes utilizingprofile data associated with the best matching instance of the libraryof calculated diffraction signals, where the calculated diffractionsignals are simulations of diffraction signals measured using an opticalmetrology device; and a simulation data store generator configured to:create an instance of a simulation data store, the simulation data storeinstance storing data elements comprising the profile data, associatedcalculated diffraction signals, simulation types, and the associatedfabrication attributes; wherein the simulation types arecharacterizations of the one or more fabrication processes simulationsperformed.
 31. A system for creating a profile-based simulation datastore for an integrated circuit, the system comprising: a profilerapplication server configured to: compare a measured diffraction signaloff a test grating in a wafer to calculated diffraction signals ininstances of a calculated diffraction signals library, the libraryinstances storing data elements comprising profile data and associatedcalculated diffraction signals, wherein the calculated diffractionsignals are simulations of diffraction signals measured using an opticalmetrology device; and select a best matching instance of the library ofcalculated diffraction signals; a device simulator configured to:simulate one or more devices, and generate device attributes utilizingprofile data associated with the best matching instance of the libraryof calculated diffraction signals; and a simulation data store generatorconfigured to: create an instance of a simulation data store, thesimulation data store instance storing data elements comprising theprofile data, associated calculated diffraction signals, simulationtypes, and associated device attributes; wherein the simulation typesare characterizations of the one or more device simulations performed.32. A system for creating a profile-based simulation data store for anintegrated circuit, the system comprising: a profiler application serverconfigured to: compare a measured diffraction signal off a test gratingin a wafer to calculated signals in instances of a calculateddiffraction signals library, the library instances storing data elementscomprising profile data and associated calculated diffraction signals,wherein the calculated diffraction signals are simulations ofdiffraction signals measured using an optical metrology device andselect a best matching instance of the library of calculated signals; adevice simulator configured to: simulate one or more circuits, andgenerate circuit attributes utilizing profile data associated with thebest matching instance of the library of calculated diffraction signals;and a simulation data store generator configured to: create an instanceof a simulation data store, the simulation data store instance storingdata elements comprising the profile data, associated calculateddiffraction signals, simulation types, and associated circuitattributes; wherein the simulation types are characterizations of theone or more circuit simulations performed.
 33. A system for creating aprofile-based simulation data store for an integrated circuit, thesystem comprising: a fabrication process simulator configured to:simulate one or more fabrication processes using a selected set ofprocess control parameters, the fabrication process simulationsgenerating fabrication attributes, the fabrication attributes includingstructure profile data; a metrology simulator configured to: receive thestructure profile data from the fabrication process simulator, andgenerate calculated metrology signals using a simulated grating, thesimulated grating having a repeating structure with the same profiledata as the received structure profile data, wherein the calculatedmetrology signals are simulations of diffraction signals measured usingan optical metrology device; a simulation data store generatorconfigured to: create instances of a simulation data store, eachsimulation data store instance storing data elements comprising theprofile data, associated calculated metrology signals, simulation types,and associated process control parameters and fabrication attributes;wherein the simulation types arc characterizations of the one or morefabrication process simulations performed.
 34. A system for creating aprofile-based simulation data store for an integrated circuit, thesystem comprising: a fabrication process simulator configured to:simulate one or more fabrication processes using a selected set ofprocess control parameters, the fabrication process simulationsgenerating fabrication attributes, the generated fabrication attributesincluding structure profile data; a metrology simulator configured to:receive the structure profile data from the fabrication processsimulator, and generate calculated metrology signals using a simulatedgrating, the simulated grating having a repeating structure with thesame profile data as the received structure profile data, wherein thecalculated metrology signals are simulation of diffraction signalsmeasured using an optical metrology device; a device simulatorconfigured to: simulate one or more devices using to profile data fromthe generated fabrication attributes; a simulation data store generatorconfigured to: create instances of a simulation data store, eachsimulation data store instance storing data elements comprising theprofile data, associated calculated metrology signals, simulation types,and associated process control parameters, fabrication attributes, anddevice attributes; wherein to simulation types are characterizations ofthe one or more fabrication or device simulations performed.
 35. Asystem for creating a profile-based simulation data store for anintegrated circuit to system comprising: a fabrication process simulatorconfigured to: simulate one or more fabrication processes using aselected set of process control parameters, the fabrication processsimulations generating fabrication attributes, to generated fabricationattributes including structure profile data; a metrology simulatorconfigured to: receive the structure profile data from the fabricationprocess simulator, and generate calculated metrology signals offsimulated gratings, the simulated gratings having a repeating structurewith the same profile data as the corresponding received structureprofile data, wherein the calculated metrology signals are simulationsof diffraction signals measured using an optical metrology device; adevice simulator configured to: simulate one or more devices using theprofile data from the generated fabrication attributes, the one or moredevice simulations generating device attributes; a circuit simulatorconfigured to: simulate one or more circuits &sing the generated deviceattributes from the one or more device simulations as input parameters,the one or more circuit simulations generating circuit attributes; asimulation data store generator configured to: create instances of asimulation data stores each simulation data store instance storing dataelements comprising the profile data, associated calculated metrologysignals, simulation types, and associated process control parameters,fabrication attributes, device attributes, and circuit attributes;wherein the simulation types are characterizations of the one or morefabrication process, device or circuit simulations performed.
 36. Asystem for creating a profile-based simulation data store for anintegrated circuit the system comprising: a metrology simulatorconfigured to: generate calculated metrology signals using input profiledata, wherein the calculated metrology signals are simulations ofdiffraction signals measured using an optical metrology device; a devicesimulator configured to: simulate one or more devices using the inputprofile data, the one or more device simulations generating deviceattributes; a circuit simulator configured to: simulate one or morecircuits using the generated device attributes from the one or moredevice simulations as input parameters, the one or more circuitsimulations generating circuit attributes; a simulation data storegenerator configured to:. create instances of a simulation data store,each simulation data store instance storing data elements comprising theprofile data, associated calculated metrology signals, simulation types,and associated device attributes and circuit attributes; wherein thesimulation types are characterizations of the one or more device orcircuit simulations preformed.
 37. A system for real-time determinationof profile-based simulation information for an integrated circuit, thesystem comprising: a query device configured to: send a query comprisingtype of inquiry for profile-based simulation data and query given data,and receive a response to the query; a simulation data store serverconfigured to: process the query and formulate the response to thequery; and a simulation data store configured to: store instances havingdata elements comprising profile data, calculated diffraction signals,and process control parameters, and fabrication attributes, wherein thecalculated diffraction signals are simulations of diffraction signalsmeasured using an optical metrology device, and wherein the simulationdata store server, receiving a query from the query device, accessesselected instances of the simulation data store, the selection of theinstances of the simulation data store determined by the type of inquiryand query given data, formulates the response to the query, andtransmits the response to the query device.
 38. The inquiry system ofclaim 37 wherein the query device is a metrology system and the querygiven data is a measured diffracted signal generated by the metrologysystem.
 39. The inquiry system of claim 38 wherein the query given datais the measured diffracted signal and the response to the querycomprises interconnect electrical device attributes from the selectedinstances of the simulation data store.
 40. The inquiry system of claim37 wherein the query given data are process control parameterscomprising focus and numerical aperture and the response to the queryare fabrication attributes comprising sidewall angle and top criticaldimension from the selected instances of the simulation data store. 41.The inquiry system of claim 37 wherein the query device, the simulationdata store, and the simulation data store server are contained in onelogical device.
 42. The inquiry system of claim 41 wherein the onelogical device is coupled to one or more integrated circuit fabricationprocess devices.
 43. The inquiry system of claim 42 wherein theintegrated circuit fabrication process device is a lithography unit. 44.The inquiry system of claim 42 wherein the integrated circuitfabrication process device is a photoresist stripping unit.
 45. Acomputer-readable storage medium containing computer executable code toprovide a response to an inquiry regarding profile-based simulation dataof an integrated circuit by instructing the computer to operate asfollows: receiving a query from a query device, the query comprising atype of inquiry and query given data; accessing a selected one or moreinstances of a simulation data store, the selection determined by thetype of inquiry and query given data; and formulating a response to thequery and transmitting the response to the query device; wherein thesimulation data store stores instances having data elements comprisingstructure profile data, fabrication attributes, simulated diffractionsignals, and process control parameters, wherein the simulateddiffraction signals are simulations of diffraction signals measuredusing an optical metrology device.
 46. A computer-readable storagemedium containing computer executable code to create a profile-basedsimulation data store for an integrated circuit by instructing thecomputer to operate as follows: performing a fabrication processsimulation using process control parameters, the fabrication processsimulation generating fabrication attributes and structure profile data;calculating a simulated signals for the structure profile data using ametrology simulator, wherein the simulated signals are simulations ofdiffraction signals measured using an optical metrology device; andcreating an instance of a simulation data store, the instance of thesimulation data store having data elements comprising the structureprofile data, the associated fabrication attributes, the simulatedsignals, and the process control parameters.
 47. A computer-readablestorage medium containing computer executable code to create aprofile-based simulation data store for an integrated circuit byinstructing the computer to operate as follows: simulating one or moredevices using a selected set of input parameters, the device simulationsgenerating device attributes, the set of input parameters includingprofile data corresponding to the one or more simulated devices;generating calculated metrology signals with a metrology simulator, themetrology simulator using profile data corresponding to the one or moresimulated devices, wherein the calculated metrology signals aresimulations of diffraction signals measured using an optical metrologydevice; and creating simulation data store instances, the instancesincluding calculated metrology signals, profile data, simulation types,process control parameters, and fabrication attributes; wherein thesimulation types are characterizations of the one or more simulationsperformed.
 48. A computer-readable storage medium containing computerexecutable code to create a profile-based simulation data store for anintegrated circuit by instructing the computer to operate as follows:simulating one or more circuits using a selected set of inputparameters, a circuit having one or more devices, the circuitsimulations generating circuit attributes, the set of input parametersincluding profile data corresponding to the one or more devices ottosimulated one or more circuits; generating calculated metrology signalswith a metrology simulator, the metrology simulator using profile datacorresponding to the one or more devices of the simulated one or morecircuits, wherein calculated metrology signals are simulations ofdiffraction signals measured using an optical metrology device; andcreating simulation data store instances, the instances includingcalculated metrology signals, profile data, simulation types, processcontrol parameters, and circuit attributes; wherein the simulation typesare characterizations of the one or more simulations performed.
 49. Amethod of providing a service for creating and using a profile-basedsimulation data store for an integrated circuit, the method comprising:contracting by a client and a vendor, for the client to remunerate thevendor for the use of systems, processes, and procedures to create anduse a profile-based simulation data store; and providing by the vendorto the client access to systems, processes, and procedures to create anduse a profile-based simulation data store, the simulation data storestoring instances having data elements comprising profile data,simulated diffraction signals, process control parameters, andfabrication attributes, wherein the simulated diffraction signals aresimulations of diffraction signals measured using an optical metrologydevice.
 50. A computer-readable medium having stored thereon a datastructure comprising: one or more instances of a simulation data store,each instance of the simulation data store including profile data,associated calculated metrology signal and one or more simulation datasegments, wherein the calculated metrology signal is a simulation of adiffraction signal measured using an optical metrology device; whereinthe calculated metrology signal corresponds to an integrated circuitstructure with a profile characterized by the profile data; wherein eachdata segment includes simulation type, associated process controlparameters or associated simulation input parameters, and associatedsimulation attributes; and wherein the associated simulation attributescomprises data determined by the simulation using the process controlparameters or the associated simulation input parameters.
 51. Thecomputer readable medium of claim 50 wherein the simulation attributesare fabrication process attributes, device attributes, or circuitattributes depending on the simulation type.